Electric switch operating mechanism



Aug. 11, 1931. L. s. WALLE 1,818,832

ELECTRIC SWITCH OPERATING MECHANISM Filed NOV. 10, 1930 Inventor: Ludwig S. Walla,

L-JWW His Attorney.

Patented Aug. 11, 1931 UNITED srares PATENT oFFrc Lunwmsr :1? LANSDQMZNEM PENNSYLVANIA, ASSIGNOR. T0 GENERAL ELIE- v 'rmc GQMPANY; A, CORPORATION or New YORK ELECTRIC OPERATING MECHANISMl Application filed November 1-930. Serial No. 494,513.

My invention: relates to electric switch operating-mechanism, and more partlcularly to means for preventing rebound of the switch mechanism upon circuit openmg movement thereof.

The operation of electric circuit breakers of. large; interrupting capacity often involves the movement of comparatively massive members at high speed so that considerable retarding force is necessary to check the mechanism at the end of its circuit opening movement. In the case of interrupting a circuit under short circuit conditions, the circuit breaker is; often opened with much greater force so that the kinetic energy of the movin parts is not entirely dissipated by the bu or structure when the end of the stroke has been reached thereby causing a tendency to rebound; This tendency to re bound is particularly objectionable since reestablishment of the are between the, separating contacts might occur if the distance between the same is appreciably decreased during; the rebound,

The principal object of m invention is the provision of an improve anti-rebound mechanism for electric switches which, shall be simple: and rugged in. construction, and positive and reliable in operation..

My invention'will be more fully set forth in the following description referring to: the accompanying drawing, and the features of novelty which characterize my invention will be pointed out, with particularity in the claims annexed to and forming apart of this s ecificationh Re 'erring to the drawings,' Fig. 1 is a :firagmentary View of switch operating mechanism embodying my invention in the closed circuit position thereoii, and Fig. 2: is av view of the same mechanism in the open circuit position thereof. 1 V

In Fig. 1 the electric switch, as an oil circuit breaker 01 73 well-known type, comprises mo-vablefrod'contacts 1 and? coacting with stationary contactstructure 3 and 4 respectively, the contact rods being interconnected by a bridging member 5 which is connected through a rod 6' with the switch actuating means generally indicated at 7. For the purpose of preventing rebound of The switch actuating means: may obviousty comprise any suitable lever. or toggle meche anism and in the present instaneecomprises: the welt known straight'linelinkage including the toggle 8 and lever 9 at the freeend of which is connected the rod 6. The toggle 8 is connected through a link 10, with one arm of a bellcrank 1'1 pivoted as at 12 and operatively connected through a lost motion connection, as the pin and slotv 'connection: 13-14, with the operating rod 15. I

The operating rod 15 may be actuated in any suitable manner, and in the present. instance is actuated through a lever16 pivoted at 17 within an operating mechanism housing 18; The lever- 16 is likewise con nected to a powerful opening spring 19. which is connected at its other end'to a fixed portion on the housing 18 and is under.- com-. pression in the closed circuit position as illustrated in Fig. 1.. I I c Where disconnecting switches: and interlocks are provided between the same) and the main circuit breaker, the operating rod 15 may be provided with an extension '20 connected in any suitable manner, as by a bellcrank 21, with a link 22 for operating the disconnecting switches in a well known manner.

In the, closed circuit position illustrated in Fig 1,, the spring 19 is in readiness to open the circuit breaker by upward movement of the; operating rod 15 and thetripping operation may be performed in any Wellknown manner by a latch or the like (not shown); releasing the lever 16: and consequently the energy stored in the opening spring. The mechanism thereupon moves to the position illustrated in Fig. 2 wherein the operating rod 15 .is in an elevated posi tion, having rotated the bellcrank 11 a corresponding amount and opened the switch contacts, In the event that the opening movement is effected with great force the actuating means may tend to rebound from its buffer structure (not shown) toward the closed circuit position; that is the bellcra'nk 11 may start to rotate counter clockwise from the position shown in Fig. 2..

the mechanism, there is provided a lug or the like 23 mounted for pivotal movement as at 24 on a fixed support which may be part of the mechanism housing 18. The lug 23 is resiliently biased, as by the adjustable sprin 25, in a clockwise direction so as to ride, y reason of the roller 26, against the side of the operating rod 15. The lug 23 is likewise provided with an abutting surface 27 offset with respect to the rod 15 and the roller 26 for engagement with a roller 28 mounted on the pin 13 carried by one arm of the bellcrank 11. The abutting surface 27 is preferably tangential to the roller 28 when in engagement therewith. WVhen the mechanism is in the closed circuit position as illustrated in Fig. 1, the lug 23 is biased by its spring 25 towards the operating rod 15 so that the roller 26 rides along the side thereof. When, however, the operating rod 15 reaches the upper limit of its stroke, that is, the open circuit position, the roller 28 carried by the bellcrank 11 rides from under the lug 23 so as to be engaged by the abutting surface 27 thereof. Gounterclockwise or rebounding movement of the bellcrank 11 is now effectively prevented since the rebound thrust is transmitted by the lug 2 3 to the stationary pivotal supportat 24, the roller 26preventing clockwise rotation of the lug 23 by the thrust transmitted thereto. Accordingly, the switch actuating mechanism may move freely to open circuit position, but upon reaching this position is positively locked by any tendency to rebound.

The circuit closing movement is effected in the usual manner by clockwise rotation of the lever 16, which is connected to the operating rod 15, causing the lower end of the operating rod to move in a generally lateral direction by reason of the pin and slot connection 13-14. During this lateral movement, the side of the rod 15 bears against the offset roller 26 and rotates in counterclockwise direction the lug 23. In other words, the downward thrust of the operating rod causes the same to move independently of the bellcrank 11 until the pin 13, which is connected to the bellcrank, is engaged by the opposite end of the slot 14. During this initial movement, the lower end 15 of the rod 15 in which is formed the slot 14, is cammed by the pin and slot connection towards the left so as to rotate the lug 23 out of engagement with the roller 28, thereby releasing the bellcrank 11 so that continued downward movement of the rod 15 rotates the bellcrank 11 in a counterclockwise direction to effect closing movement of the circuit breaker. During this movement the roller 26 rides on the side of the rod 15 as illustrated in Fig. 1. Accordingly, the anti-rebound mechanism does not in any way hinder the normal operation of the circuit breaker, while functioning in a positive manner to prevent rebound.

It shall be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Electric switch operating mechanism comprising an operating member, electric switch actuating means, a lost motion connection, between said member and actuating means, and a member having a fixed pivot adapted to engage said actuating means in the open circuit position thereof for preventing rebound thereof, said operating member operable through said lost motion connection to disengage said pivoted member in response to circuit closing movement thereof.

2. Electric switch operating mechanism comprising an operating rod, electric switch actuating m e a n s operatively connected through a lost motion connection with said rod, a lug pivotally mounted on a fixed support for engaging said actuating means in the open. circuit position thereof for preventing rebound, and means for resiliently biasing said lug towards said operating rod and into engagement with said actuating means, said operating rod operable to move said pivoted lug out of engagement with said actuating means upon initial circuit closing movement of said rod and prior to its operative connection to said actuating means through said lost motion connection. I

3. Anti-rebound mechanism for electric switches comprising an operating rod, switch actuating means, a pin and slot connection operatively connecting said rod with said actuating means, a lug pivotally mounted on a fixed support resiliently biased towards said operating rod and said actuating means, said actuating means including a roller coacting' with an abutting surface on said lug in the open circuit position of said actuating means for preventing rebound thereof, said abutting surface being substantially tangential to saidroller, and a portion forming part of said operating rod operable to move said lug out of engagement with said roller upon initial closing movement of said operating rod and prior to operative engagement with 'said actuating means through said pin and slot connection.

4. Anti-rebound mechanism for electric switches comprising an operating rod, switch actuating means including a bellcrank operatively connected through a pin and slot connection with said rod, a, lug pivotally mounted on a'fixed support coacting with a roller carried by said bellcrank for preventing rebound of said actuating means after circuit opening movement thereof, means for resiliently biasing said lug towards said operating rod and into abutting engagement with said roller, a roller carried by said lug in following engagement with said operating rod, and means forming part of said operating rod movable independently of said actuating means through said pin and slot connection for moving said lug out of engage l0 ment with said bellcrank roller upon initial circuit closing movement of said operating rod.

In witness whereof, I have hereunto set my hand this 4th day of November, 1930. LUDWIG S. WALLE. 

